A polymer lithium ion battery is a new secondary battery system with high specific energy based on a liquid lithium ion battery. Generally, the polymer lithium ion battery comprises a negative plate, a positive plate and a polymer composite electrolyte located between the negative plate and the positive plate, in which the positive plate comprises a positive current collector and a positive active material, the negative plate comprises a negative current collector and a negative active material, and the positive active material and the negative active material are located oppositely in the battery shell. Compared with a conventional liquid lithium ion battery, the polymer lithium ion battery has following advantages. Firstly, the use of a polymer composite electrolyte instead of a liquid electrolyte solution may effectively avoid the problem of electrolyte solution leakage of the liquid lithium ion battery, thus ensuring a high reliability of the battery. Secondly, the use of a light soft plastic shell instead of a metal shell may not only decrease the weight of the battery shell effectively to improve the specific energy of the battery, but also may lower the probability of the risks such as explosion and burning to enhance the safety performance of the polymer lithium ion battery. Thirdly, it is convenient to design the shape of the polymer lithium ion battery to develop ultrathin, mega-sized and various shaped batteries.